'85 90hp dies after 5 min., restarts & dies again.

[paid4]

Last fall my '85 90hp Evinrude VRO died one day. We just hit the water, threw out the tube, and made about 4 passes draggin' kids when it slowed and then stopped. (Doesn't bog or accelerate-decelerate, just slowed & stopped.) I assumed I needed to switch tanks, but it wasn't really the "out of gas" kind of sound. I switched tanks and it fired back up. Ran it again, died after a minute or two. Thought maybe I forgot to open the vent on the can, so checked that, but it was fine. Fired it up again, did the exact same thing. It would start up, idle just fine, but died when pulling a tube. Idled it into shore and loaded it up. It was near quitting time anyway, so I put it away for the winter and figured we'd address in spring. I dragged to the local shop (not real local where I live on the prairie) and about a week ago they finally got to it. They said "couldn't find anything wrong. Runs fine." I asked them if they let it get hot and if they ran it under load, and of course they said "yes we did." Okay. So I took it out Monday night to the local reservoir for a shake down, running circles close to the ramp. Sure enough, ran fine on low speed for 1-2 minutes, but died after about 3-4 minutes opened up. Would restart, idle, then die after about 1 minute wide open. Tried pumping the fuel bulb to no avail. Idled back to the dock, you get the drill. Not too excited about hauling it back to same shop. Ideas? Suspecting electrical vs. fuel, not sure how to know. Need to know how to convince the shop to diagnose it right and fix it right.

 

[emdsapmgr]

Re: '85 90hp dies after 5 min., restarts & dies again.

Some things you can check for: 1. take a laser temp gun with you next time out. When the engine slows unexpectedly, check the cyl head temps. They should be in the 145-150 range-not much higher. 2. when the engine shuts down, pull the plugs. see if they are wet or dry-that will tell you something. 3. Also when it stops on the lake, use an inductive timing light to check for spark on each of the 4 plug wires. If the engine stops, just crank it to check for spark. The flashes from the gun will tell you if it's misfiring, weak, not firing at all.

 

[paid4]

Re: '85 90hp dies after 5 min., restarts & dies again.

Sad but true tale--switch mechanics, brought it to shop with your post, they bothered to actually do more than just start the engine, run it in neutral two minutes, and turn it off. VRO not oiling (plugs very dry), two cylinders not holding, mechanic suspects that when it got hot it simply seized/shut off. Turns out the oil horn did not work. In ball park figures, I think we're looking at a third strike called. Not convinced it's worth it to rebuild an '85. I guess I should've listened to all the folks who told me to jerk the VRO and stick in a conventional with pre-mix. :facepalm: